1. Field of the Invention
The present invention relates to a driving apparatus for a light emitting diode, and more particularly, to a driving apparatus which can increase the refresh rate in a scan application.
2. Description of Related Art
Because light emitting diodes (LED) are small in size, power-saving and durable and their prices are getting lower with maturing of fabrication thereof, products that have LEDs as a light source have been widespreadly used in recent years. The LEDs are widely used in various terminal devices ranging from automobile headlamps, traffic lights, text displays, bulletin boards and large-sized video displays, to ordinary and construction illumination and LCD backlighting applications.
A typical LED display mainly includes an array of LEDs. A pixel of the image consists of red (R), green (G) and blue (B) portions. Each portion can consist of one or more LEDs. In displaying the image, adjusting the brightness of the red, blue, and green of the pixels can result in different colors. Image refresh rate refers to the rate of refreshing images on the screen. Image refresh cycle is the reciprocal of the image refresh rate, which indicates the time an image stays. To reduce the cost of the displays, the number of the driving circuits used can be significantly reduced by increasing the LED driving current in combination with the use of a scan technology. Because the LEDs are current-driven devices which are limited by the current driving capacity and transforming capacity of the LED driving circuits, the image refresh rate cannot be effectively increased.